Returns a list created by splitting string at each character
that is in the splitChars argument.
Each element of the result list will consist of the
characters from string that lie between instances of the
characters in splitChars.
Empty list elements will be generated if string contains
adjacent characters in splitChars, or if the first or last
character of string is in splitChars.
If splitChars is an empty string then each character of
string becomes a separate element of the result list.
SplitChars defaults to the standard white-space characters.